1. Technical Field
The present invention relates to a liquid-crystal apparatus, a method for manufacturing the liquid-crystal apparatus, and an electronic device equipped with the liquid-crystal apparatus.
2. Related Art
Liquid-crystal apparatuses have an element substrate and another substrate facing it, namely, an opposite substrate. The element substrate has pixel electrodes formed thereon, and the opposite substrate and the element substrate sandwich a liquid-crystal layer therebetween. The element substrate has some more elements and layers placed thereon; for example, pixel transistors, pixel electrodes, an insulating coating, and an oriented coating are layered in this order. Preferably, the uppermost layer of the element substrate is flat. Some measures can be taken to achieve this. A possible solution is to seal depressions, which are due to the formation of contact holes or the presence of pixel electrodes, in the lower layers with a metal coating or the insulating coating. A typical case can be seen in a structure in which a lower conductive layer and pixel electrodes are electrically connected via contact holes formed in an interlayer insulating coating. This type of structure allows depressions to be formed beneath the oriented coating to spread over the inner wall of the contact holes. Thus, the contact holes (depressions) are plugged up with a coating made of molybdenum, tungsten, or some other appropriate metal.
However, as described in JP-A-10-39332, plugging up all depressions requires forming a metal coating to a thickness enough for the complete sealing of the depressions and subsequently grinding the metal coating. Unfortunately, the constitutions described in this publication are unfavorable in terms of productivity because it takes a long time to form the metal coating and grind it and for other reasons. To make matters worse, this method is costly; it involves the use of a coater that can produce a metal coating of good step coverage and the use of a grinder for metal surfaces, and such machines are usually expensive.